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        <h2>
          <span class="refentrytitle">dcblock</span>
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        <p>dcblock — 
      A DC blocking filter.
    </p>
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      <div class="refsect1">
        <a id="idp97978160"></a>
        <h2>Description</h2>
        <p>
      Implements the DC blocking filter
      </p>
        <div class="literallayout">
          <p><br />
Y[i] = X[i] - X[i-1] + (igain * Y[i-1])<br />
      </p>
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        <p>
    </p>
        <p>
      Based on work by Perry Cook.
    </p>
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      <div class="refsect1">
        <a id="idp97981088"></a>
        <h2>Syntax</h2>
        <pre class="synopsis">ares <span class="command"><strong>dcblock</strong></span> ain [, igain]</pre>
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      <div class="refsect1">
        <a id="idp97983328"></a>
        <h2>Initialization</h2>
        <p>
      <span class="emphasis"><em>igain</em></span> -- the gain of the filter, which defaults to 0.99
    </p>
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      <div class="refsect1">
        <a id="idp97985088"></a>
        <h2>Performance</h2>
        <p>
      <span class="emphasis"><em>ain</em></span> -- audio signal input
    </p>
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              </td>
              <th align="left">Note</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>The new <a class="link" href="dcblock2.html" title="dcblock2"><em class="citetitle">dcblock2</em></a> opcode is an improved method of removing DC from an audio signal.</p>
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      <div class="refsect1">
        <a id="idp97988432"></a>
        <h2>Examples</h2>
        <p>
     The result can be viewed in a graphical audio editor program like <span class="emphasis"><em>audacity</em></span>. <span class="emphasis"><em>audacity</em></span> is available for Linux, Windows, and the MacOS and may be downloaded from <a class="ulink" href="http://audacity.sourceforge.net/" target="_top"><em class="citetitle">http://audacity.sourceforge.net</em></a>.
    </p>
        <p>
      Here is an example of the dcblock opcode. It uses the file <a class="ulink" href="examples/dcblock.csd" target="_top"><em class="citetitle">dcblock.csd</em></a>, and <a class="ulink" href="examples/beats.wav" target="_top"><em class="citetitle">beats.wav</em></a>.
      </p>
        <div class="example">
          <a id="idp97993424"></a>
          <p class="title">
            <strong>Example 172. Example of the dcblock opcode.</strong>
          </p>
          <div class="example-contents">
            <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
            <pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
-odac     <span class="comment">;;;RT audio out</span>
<span class="comment">;-iadc    ;;;uncomment -iadc if RT audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">;-o dcblock.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 32
<span class="ohdr">nchnls</span> <span class="op">=</span> 2

<span class="oblock">instr</span> 1	<span class="comment">;add DC to "beats.wav"</span>

asig <span class="opc">soundin</span> "beats.wav"
asig <span class="op">=</span> asig<span class="op">+</span>5000	<span class="comment">;adds DC of 5000</span>
     <span class="opc">outs</span> asig, asig
<span class="oblock">endin</span>

<span class="oblock">instr</span> 2	<span class="comment">;dcblock audio</span>

asig <span class="opc">soundin</span> "beats.wav"
asig <span class="op">=</span> asig<span class="op">+</span>5000	<span class="comment">;adds DC</span>
adc  <span class="opc">dcblock</span> asig	<span class="comment">;remove DC again</span>
     <span class="opc">outs</span> adc, adc

<span class="oblock">endin</span>

<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>

<span class="stamnt">i</span> 1 0 2
<span class="stamnt">i</span> 2 2 2
<span class="stamnt">e</span>

<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre>
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        <p><br class="example-break" />
      
    </p>
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      <div class="refsect1">
        <a id="idp97997760"></a>
        <h2>See also</h2>
        <p>
          <a class="link" href="dcblock2.html" title="dcblock2">
            <em class="citetitle">dcblock2</em>
          </a>
        </p>
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      <div class="refsect1">
        <a id="idp97999616"></a>
        <h2>Credits</h2>
        <p>
      </p>
        <table border="0" summary="Simple list" class="simplelist">
          <tr>
            <td>Author: John ffitch</td>
          </tr>
          <tr>
            <td>University of Bath, Codemist Ltd.</td>
          </tr>
          <tr>
            <td>Bath, UK</td>
          </tr>
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        <p>
    </p>
        <p>New in Csound version 3.49</p>
        <p>February 2003: Thanks to a note from Anders Andersson, corrected the formula.</p>
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